1. Field of the Invention
This invention relates to exhaust diffusion apparatus for internal combustion engines. More particularly, it relates to diffusion apparatus intended to minimize operational noise levels to acceptable levels.
2. Description of the Prior Art
High performance engines such as are found in racing boats, racing cars, motorcycles and the like, often include an exhaust system substantially devoid of noise level control. This is necessarily the case, since performance is the primary concern. Noise level control typically interposes restrictions to flow which substantially impede performance.
Often, vehicles of the type described are operated where noise level control is desired, if not mandatory. Many municipalities have enacted ordinances against excessive noise and which impose substantial fines for violations. Operation within the jurisdiction of such a municipality dictates the need for noise reduction.
Efforts have been made to provide diffusion apparatus to reduce the noise level of high performance engines. One example is a product marketed under the mark "SUPER TRAPP" by Gil Marine, Westminster, Calif. This device is adapted to attach to the exhaust system of a high performance racing boat. It includes a plurality of spaced rings which define a plurality of annular paths through which exhaust may pass. The number of rings, and thus, the number of annular exhaust passages, may be varied to vary noise output level. It has been found, however, that to achieve sufficient noise reduction, performance is irreparably impaired, rendering the engine useless for its intended operational mode.
It is the main objective of the present invention to provide an improved diffusion device which effectively dampens exhaust sound where necessary, and permits optimum performance when performance is the intended goal.